wine-whine merger

noun1

1. •
   A merger in which [ʍ] (the voiceless sound heard at the beginning of the word whine in a Scottish accent or several accents in the United States) becomes [w] (the sound heard at the beginning of the word wine); in accents where this merger occurs, whine and wine are homophones.

   • As was the case with the wine–whine merger, date from the early twentieth century show that southeastern Pennsylvania was subject to patterns of variation in pronunciation. — 2016